<html xmlns="http://www.w3.org/1999/xhtml">
        <head>
                <title>Testcase</title>
        </head>
        <body onload="document.getElementById('B').appendChild(document.getElementById('A'));">
                <div style="position: relative;">
                        <math xmlns="http://www.w3.org/1998/Math/MathML">
                                <mover>
                                        <mrow id="A"/>
                                        <mn id="B"/>
                                </mover>
                        </math>
                </div>
        </body>
</html>
